Water impoundment areas are integral aspects of land and water management both in modern and ancient times. These areas can be generally characterized as areas of land that hold non-flowing water originating from natural flowing water sources or man-made water sources. Impoundment areas can be areas set aside for controlling water quality, such as settling ponds, in which sediment and impurities are allowed to settle out of a body of water before the water is allowed to be transported downstream. Modern land and water quality management practices still rely on use of impoundment areas including settling ponds and other non-flowing bodies of water. Landscapes are often altered in agricultural and industrial efforts in which natural drainage must be changed to prevent undesirable erosion or damage to the altered landscapes. Alteration may inevitably create excess sediment and may introduce undesirable minerals or other pollutants into a drainage area. Government regulation also plays an important factor in water management, and government water quality standards may require water to be impounded and treated prior to release of water from a regulated activity.
Some basic principles for construction and maintenance of impoundment areas are common to both modern and ancient times. One basic principle is that the water to be impounded is held in a basin until settling of sediments and impurities can occur. If a rain event or other cause of flooding results in overflow of the basin, then another principle is to allow only the top of the water column to be discharged downstream, either by overflowing the bank or spillway of the basin, or by water flow control over a water control device incorporated within the basin. Since the top of the water column almost always contains the purest water, sediment, contaminants, and other non-desirable materials are held in the settling pond while the top of the water column may be released. This simple method of water control has been documented to greatly improve downstream water quality while virtually eliminating on-site soil erosion.
One common form of a water control device or gate is referred to as a “flashboard riser”. This type of water control gate may be constructed of a barrier housing, such as a half pipe shaped member cut from culvert pipe material, with a drain pipe connected to an opening formed in the housing. The flashboard riser is typically installed within an earthen dam such that the earthen dam covers the drain pipe. The front face of the housing is immersed in the water. The drain pipe communicates with a downstream drainage device or another body of water. The front face of the housing has aligned slots which receive cut boards placed in the slots. The boards form a wall of a selected height depending on the number and width of the boards chosen. The impoundment of water is achieved in which only the top of the water column is able to be discharged as it overflows or overtops the top board of the riser. Boards can be added or removed one at a time to account for changes in the level of the water in the basin or settling pond, thereby providing a simple yet reliable means of incremental control for discharge of water from the settling pond. Examples of where these types of flashboard risers are typically installed include agricultural fields surrounded by relatively low levees, wooded areas where water may be held periodically, and construction sites where soil is disturbed and runoff water impoundment is required.
Although traditional flashboard risers have great utility in diverse water containment applications, there are a number of problems associated with these risers. For example, boards must be individually cut for the housing of each riser. In agricultural applications, farmers may have numerous types of flashboard riser with housings that each requires different sized boards in terms of both width and length. It is known to use boards with interlocking edge surfaces, but these still suffer some amount of leakage and therefore, plastic sheeting may be required to better seal the riser from leakage between boards. Plastic sheeting also becomes a problem in that it must be manually installed with the boards, and it is difficult to effectively encapsulate the boards exposed to water in the pond. Wooden boards swell over time as they immersed in water, thereby making it difficult to remove the boards from the slots in the housing. In general, boards cannot be reused, and are difficult to raise or lower once installed.
Various types of automatic water control gates are available, but these water control gates are relatively expensive to purchase and install. Due to cost constraints, particularly for agricultural applications in which a large number of flashboard risers may be required, it is not economically feasible to install an automatic water control gate at each required location.
Therefore, there is a need to provide a simple yet reliable water control device that can function similar to a traditional flashboard riser, but which avoids manual labor disadvantages associated with cutting and replacing boards. There is also a need to provide a water control device in which incremental control is achieved with respect to the height of the water column allowed to overflow the water control device. There is also a need for the incremental control of the height of the water column released by the water control device to be achieved with minimal or no manual effort to adjust or manipulate each water control device. There is also need to provide a water control device that reduces operator time and effort associated with standard operation and maintenance.